The present invention relates to an electronic component and a method for manufacturing the same. More specifically, the present invention relates to a technique for forming a conductor such as a terminal electrode on an outer surface of a chip-shaped electronic component (hereinafter also simply referred to as a chip in some cases).
Electronic components including various discrete components such as chip capacitors, chip inductors or chip resistors, and various electronic devices formed by combining multiple active and passive elements are offered today. Any of these electronic components needs terminal electrodes provided on the outer surface thereof so as to establish electrical and mechanical connection with the outside, thus being mounted on a wiring board.
Such a terminal electrode has heretofore been formed, for instance, by: printing and coating a conductive material (a conductive paste or a conductive resin) at a predetermined position and in a predetermined shape by use of a mask for each chip which has been functionally configured; then performing hardening and baking processes; and subjecting the terminal electrode to plating as appropriate. The layout of the electrode is generally formed into a “U” shape in which the electrode is disposed on three surfaces of: a top surface (a front surface); a bottom surface (a rear surface); and a peripheral surface (a side surface or an end surface). Alternatively, the layout of the electrode is formed into an “L” shape in which the electrode is disposed on two surfaces of: the peripheral surface; and either of the top surface or the bottom surface.
The electrode on the top and bottom surfaces is provided for the purposes of: mounting the chip on a substrate, establishing an electrical connection to wiring on the substrate, evaluating the characteristics, and the like. Meanwhile, the electrode on the peripheral surface is provided as a wiring section for drawing the conductor inside the component out to a mounting surface of the substrate. Moreover, this electrode plays the role for mechanically fixing and retaining other components in addition to establishing electrical connection to the substrate.
As for procedures to form the terminal electrodes, a wiring layer which become a functional composition section of the electronic component, an insulating layer, a function layer, a protective film layer, wiring exposed sections for establishing connection to the terminals, and the like collectively constituting a functional composition section of the electronic components are formed in a combination board (or a wafer), and then this board is cut into individual chips. Thereafter, the terminal electrodes are formed on one or both of the top and bottom surfaces of each chip, and formed on the peripheral surfaces of the chip so as to extend in a perpendicular direction. The electrodes on the top and bottom surfaces may be formed in advance in the step of forming the functional composition section, and the order of formation of the terminal electrodes varies in consideration of bonding quality or ease of electrode formation. Further, in order to reduce the number of processes for forming the terminals, there is also known a method of forming the electrodes simultaneously on the top and bottom surfaces of the chip by delivering an electrode material onto those surfaces during formation of the electrode on the peripheral surface of the chip, which is assisted by chamfering (or so-called “rounding”) the corner of the chips.
On the other hand, it is also possible to apply a thin-film method instead of the above-described thick-film method. Specifically, electrode films are formed by use of a vapor deposition system such as a sputtering system or an evaporation system while each chip is fixed with a jig and covered with a mask. In order to form the electrode on multiple surfaces, it is only necessary to change the orientation of the chip and to repeat the film forming process similarly. Moreover, terminals are further plated on the thin film thus formed when it is appropriate.
The following patent documents also disclose a technique for forming such terminal electrode:
(1) Patent Document 1: Japanese Unexamined Patent Application Publication No. Heisei 7 (1995)-254534 (JP-A-7-254534);
(2) Patent Document 2: Japanese Patent No. 3613091 (JP-B-3613091); and
(3) Patent Document 3: Japanese Unexamined Patent Application Publication No. 2004-289085 (JP-A-2004-289085).